David h



D. H. MORRISON.

V I Bridge Truss.

' No.. 70,245. I Patented Oct. 29, 1867.

stra t titre.

n'iteh tates DAVID n. MORRISON, OF DAYTON, onto.

Letters Patent 1V0. 70,245, dated October 29, 1867.

IMPROVED IRON BRIDGE- TO ALL WHOM IT MAY CONCERN:

Be it known that I, DAVID H. MORRISON, of Dayton, in Montgomery county,in the State of Ohio, have invented a new and useful Improvement in IronBridges; and I do hereby declare that the following is an exact and fulldescription thereof, reference being had -to the accompanying drawings,and to the letters of reference marked thereon.

Figure 1 is a side elevation of a truss of my improved bridge.

Figure 2 is a transverse sectional view of the same taken at the line at:v of fig. 1.

Figure 3'is a portion of the arch and one of the posts, with thearch-joint washer, and the arch-joint plate, the flanges at one side ofthe arch-rail being broken away to exhibit the parts, including theconcave washers for supporting the diagonal brace-hooks. This figure isa longitudinal section of that portion of fig. 1 between the red lines 2a.

Figure 4 represents the universal washer.

Figure 5 represents a modification of the arch in section.

Figure 6 represents the hook-bolt supporting washer.

Figure 7 represents the eye-bolt supporting washer, and

Figure 8 represents the skew-back detached.

My invention relates to the method ofjointing and arranging I-shapedwrought-iron beams or channel-bars in a bridge-truss, and to the devicesby which the bridge structure is connected and supported.

The arch represented in fig. 1 is what is denominated a broken-linearch, all the joints of which are true radial lines of the arch.

In the accompanying drawings, A denotes the chord, which is constructedof two fiat bars of iron, seen at a a in fig. 2, which are placedparallel to each other, about one and a quarter inch apart, to allowsuificient space for splicing-pieces, the ends of the posts 6, thediagonal trussing eye-bolts e e, and the lugsfof the universal Washer33. The posts I; have holes through their lower ends, through whichdye-bolts s are inserted, which secure the posts between the flat bars aa. But one of the eye-bolts with its washer is represented in fig. 1 ofthe drawings. The eye-bolts s'serve for fastenings for horizontaldiagonal brace-rods, which would occupy a position under thebridge-floor. The beams C of the arch are of equal length, and they arejointed or bevelled uniformly at the same angle at their ends, exceptingthe ends of the pieces which rest against the skew-backs D D, andconsequently these beams will fit any position in the arch by bringingthe bevelled jointed ends together, as

represented in fig. 1. The beams G are arranged with their "doubleflanges in vertical planes, which willcause the web of the beams to bein a position at right angles to a vertical plane. In other words, thetransverse direction or lineof the web will be at right angles to thevertical plane occupied by the flanges of the beams. At each joint ofthe arch the washers iz'arc placed upon the webs of the beams, the upperends of the posts 6 passing through them, and nuts on the ends of postsI; hold these washers firmly down upon the joint of the arch. The postsare bent slightly near their upper ends, where they pass through thearch-joints, so as to bisect them and form a secure fastening; andunderneath each joint of the arch, and resting upon the shoulders of theposts, there are placed arch-joint plates 9 9, to strengthen thearch-joints, and, the hook-boltspp pass through the plates g, and theweb of the arch-beams, as represented in fig. 3. The hook-bolts areprovided with a supporting .washer, (fig.'6,) so formed with a concavedepression as to form a seat or rest for the shoulder of the hook, and

prevent sudden strain upon the diagonals b 6 from bending or breakingoff the hooks. The washer represented in fig. 7 is similarly formed,with a depression corresponding with the shape of the shoulders of theeye-bolt s, and for the same purpose. that the hook-bolt washer is made.The universal washer B is provided with the longitudinal opening throughits centre, indicated by dotted lines, for the diagonal brace-rods b bto pass through, and the lugfis inserted between the chord-bars a a, anda bolt secures the washer in place. These washers being made with anenlarged opening for the diagonal rods, and with the curved faces forthe nuts, it will be apparent that the nuts, and the diagonal bracesupon which the nuts are screwed, will both adjust themselves in properrelation to the line of the connections between the arch and chord,whatever may be the angle which they occupy. Therefore I denominate thewasher represented in fig. 4 as a universal washer. In forming the archor post of three I beams, they will be connected together, asrepresented in sectional fig. 5. The com tral beam forms the web, whichwill, like the web of'the arch-beams, in fig. 1 have its cross-sectionat right angles to a vertical plane. This construction will afiord greatstrength, and prevent any liability of the arch becoming kinked orswayed laterally. The bulk of the metal forming the arch, in either ofthe modifications represented, being in the flanges, and lateral to theweb, and at thesame time at the greatest distance from the axis orcentral longitudinal line of the arch, the greatest resistance will beexerted against any tendency of the arch to sway laterally; the greatobject being to so dispose the material as to secure the greateststrength with the least weight of metal, which can best be accomplishedby an arrangement which shall insure the truss against lateralinclination, as herein described. One of the advantages of my improvedconstruction of bridges is in the method of fitting the joints of thearch-beams which are bevelled at their ends uniformly, and being of thesame length, they will fit accurately and form perfectjoints in anyportion of the arch, and therefore all the beams composing the arches ofa bridge may be constructed by the same uniform rule. -The universalwasher is equally adaptable to use in any position in the chord, withoutregard to the length of the span of the bridge, or to the angle whichthe diagonal brace-rod which connects the arch with the chord occupies.

The chord-bars a a, represented in fig. 8, extend through the eye of theskew-back, as indicated in dotted lines, and being doubled over at theirends and welded, are of the double thickness represented at pp,,andametal block, 1", is inserted between them, which forces them laterallyagainst the sides of the square enlargement n, in the end of theskew-back D, which enlargement forms shoulders 0, against which theshoulder on the chord-bars would rest. Wedges s 8' may be insertedbetween the returned ends of the chord-bars and the shoulders of theenlargement of the skew-back, by which means the chord may be tightenedor strained longitudinally. After the chord-bars a a are insertedin theopening in the skew-back, the block 1" will be inserted, and a bolt, q,may be employed to secure the chord-bars and block 1* together. 2 2indicates the seat of the skew-back, against which the end of theI-shaped arch-beam or channel-bar will" rest. The chord-bars may betightened by means of a nut, as seen in fig. 1 or by means of thewedges, as represented in fig. 8.

I Having fully described my improvements in iron bridges, what I claim,and desire to secure by Letters Patent, is-

1. The universal washer Bf, constructed and applied in the manner andfor the purpose specified.

2. The combination andxarrangement of the arch-beams C, arch-jointplates g, and universal washerB f, when constructed, connected,,andoperating conjointly in the manner and for the purpose described.

In testimony whereof I have hereto set my hand this 19th day of April,1867. D. H. MORRISON. Witnesses:

H. P. K. PEcK,

A. L. PEcK.

